Josh Scott from JHS breaks overdrive pedals down into five core circuit types, showing what actually separates one "drive" pedal from another.
Soft clipping pedals split into two families. Tube Screamer style circuits boost the midrange, pushing your guitar forward in a mix with a thicker, more saturated feel. Blues Breaker style circuits stay transparent, adding grit without reshaping your tone.
Hard clipping pedals put the diodes at the end of the circuit, so the whole signal gets clipped. That makes them rawer and less forgiving, with the DOD 250 and MXR Distortion Plus as the reference points.
The Klon Centaur gets its own category. It's a hard clipper, but a dual-pot gain control blends in your clean signal, so it stays articulate even at high gain, unlike other hard clippers.